law enforcement, they will tell you they need things like a national registry of gun sales tracing technology. so when crimes occur, they're able to trace them back. law enforcement says they need background checks and the nra has opposed a comprehensive background check policy. 80% of violent crimes come use -- using firearms, come from the sales of unlicensed users. such as gun shows. >> one of the things i found ironic is you found how we need a better data base system for the mentally ill. but no mention of the work that his organization has done to block as you say these data bases that would better track gun sales as well as do background checks. >> that's right. they have opposed the states cooperating with the federal system. a national registry of mentally ill. they have as i said opposed all of the tools that law enforcement has asked including extending background checks responsible for most of the guns sold and used in violent crimes. the second is this doozy that guns are for self-deference. when we know as basic silence and data that if you have a gun in your home, you're 22 mor